Metals and their uses

Extracting Metals

Anoreis ametal compounddeep underground that isworth extracting.This depends on: How muchof the metal the ore contain How easyit is to extract the metal from its ore (e.g. the methods used for extraction e.g. electrolysis/ reduction / photomining etc)

From the last bullet point, you can tell that some ores can become worth extracting ifnew methodsare discovered to extract an ore.Some metals, like gold and silver, are sounreactivethat they existpurelyas the metal itself; in theirnative state.

How a metal is extracted from its ore once the ore is harnessed really depends on where it lies in thereactivity series. If the metal ismore reactivethan carbon, the metal will have to be extracted throughelectrolysis. But if the metal isless reactivethan carbon, it can bereducedanddisplacedfrom its ore to produce themetal itselfandcarbon dioxide.

Some metalsreactwith the carbon so we have to usesomething differentto displace it e.g.Titaniumbecomesbrittleif extracted using carbon as it reacts with the carbon, sodium or magnesium is used instead.

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Iron

Iron isless reactivethan carbon so can used toreduce + displaceit in a blast furnace

iron (iii) oxide + carbon > iron + carbon dioxide

Cast iron:

·Contain96% iron

·The4% impuritiesare mostly carbon

·Hard

·Brittle

·Can’tbe easilycompressed

·Can be run intomouldsand cast intodifferent shapes

·Used to makewood burning stoves, man hole coversonroadsandengines

Pure iron:

·Verysoft

·Easilyshaped

·Notveryuseful

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Carbon Steels

Steel = Alloyed iron (an alloy is a mixture of metals)

Low carbon steels

· Contains less than 0.1% carbon

· Soft, easily pressed into shape

· Not as strong as HCSs

Used for car bodies, Knives, machinery, ships, containers, and structural steel for buildings.

High carbon steels

· Contains 0.1-1.5% carbon

· Very strong

· Brittle – likely to shatter

Used for car bodies, knives, machinery, ships, containers, and structural steel for buildings

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High and Low Alloy Steels

Low alloy steels

· Contain 1-5% of other metals

· Controlling amounts + type of metal > desirable properties

Use depends on alloy design

High alloy steels – e.g. Stainless Steels

· Contain a much higher percentage of other metals

· e.g . Chromium – Nickel

· Hard

· Strong

· Resistant to corrosion; do not rust

Used for cooking utensils/ Cutlery, chemical reaction vessels

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Aluminium

Aluminium:

Silvery, shiny metal; attractive

Surprisingly light; has a relatively low density

An excellent conductor of energy + electricity

Malleable + Ductile

Very resistant; does not corrode easily because of the thin layer of aluminium oxide it forms when in contact with the air, which stops any further reactions from taking place